Laser C bug

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Article #31283

#31283

From: braner
Date: Tue, 15 Mar 1988 21:42

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The Laser C preprocessor will not take a logical OR, as in:

#define AtST  1
#define MSDOS 0
...
#if (AtST || MSDOS)		/* does not work! */

The solution is to write:

#if (AtST | MSDOS)		/* this does work */

Note that the replacement of logical OR with a bit-wise OR is safe,
but one CANNOT generally replace "&&" with "&".  For example:
(2 && 4) == 1, but (2 & 4) == 0.

I consider this a bug since in "C: A Reference Manual" by Harbison & Steele
(highly recommended, look for 2nd edition!) it says explicitly that "||"
is OK in the constant expression for #if.

- Moshe Braner

PS:  Havn't received the Laser C manual yet.  I sent the defective Laser C
system disk I got back to Megamax, and they sent me a replacement already.

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Message-ID: <4057@batcomputer.tn.cornell.edu>

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Path: arc1-ca.pugleaf.net!utzoo!mnetor!uunet!husc6!mit-eddie!uw-beaver!cornell!batcomputer!braner
From: braner@batcomputer.tn.cornell.edu (braner)
Newsgroups: comp.sys.atari.st
Subject: Laser C bug
Message-ID: <4057@batcomputer.tn.cornell.edu>
Date: 15 Mar 88 21:42:00 GMT
Reply-To: braner@tcgould.tn.cornell.edu (braner)
Organization: Cornell Theory Center, Cornell University, Ithaca NY
Lines: 25
Summary: Preprocessor #if can't take "||"